The reduction of noise is important to improve environmental conditions.
This invention relates to the reduction of undesirable noise generated by a wide variety of sources. In particular, this invention is advantageously utilized to reduce undesirable noise generated by fans in industrial and utility applications. Usually such fans run under relatively steady state conditions.
Many techniques and systems are known for reducing noise generated by noise generators such as fans. The generation of noise is, of course, a consequence of the normal effective operation of machinery such as a fan. The term "noise generator" is used to broadly mean a mechanical operative item which, as a result of its operation, generates noise. The known systems invariably require a transducer located in the vicinity of the noise generator, cancellation means located in the vicinity of the noise transducer and an electronic controller between the transducer and the cancellation means. According to the noise generated by the transducer, suitable signals are caused to be generated by the controller means to the cancellation means. The signals generate a noise pattern to counteract the effect of the noise generated by the noise generator.
Unfortunately, the known systems for reducing the noise of the noise generators often require multiple transducers located in relatively harsh environments relative to the noise generator. Also, the electronic controller is not often tuned to provide the best anti-noise control to the system.
It is accordingly an object to the present invention to provide a system for reducing the noise of a noise generator such as a fan, in a manner which is improved over the prior art techniques.